Chronic pain accounts for billions of dollars of lost productivity and medical expenses annually. Current treatment strategies suffer from partial efficacy across the population, resulting in inadequate pain relief. Furthermore, many chronically administered analgesics (e.g., morphine or oxycontin), while actually effective, lead to tolerance and addiction. Consequently, it is imperative to identify novel drug targets for the development of non-addictive analgesics. Bioactive lipids such as endocannabinoids and N-acylethanolamines (NAEs) regulate nociception throughout the nervous system. Preclinical studies suggest that modulation of endocannabinoid and NAE catabolism represents an attractive strategy for the treatment of pain that is also devoid of psychotropic effects. Recently we identified fatty acid binding proteins (FABPs) as the first intracellular carriers that regulate endocannabinoid and NAE transport and inactivation in vitro. To date, it is not known whether FABPs regulate the endocannabinoid and NAE tone in vivo. The central goals of this project are to determine whether FABPs regulate endocannabinoid and NAE signaling and inactivation in vivo and to ascertain whether inhibition of FABPs produces endocannabinoid- and NAE-mediated antinociception. We will accomplish this by first determining whether ablation of FABPs reduces nociception in models of inflammatory pain. We will then identify the FABP subtypes that modulate pain and inflammation through a combination of complementary approaches: pharmacological manipulation and transgenic FABP knockout mice lacking specific subsets of FABPs. In the second aim of this proposal, we will employ mass spectrometry-based lipidomics to determine whether FABPs regulate endocannabinoid and NAE levels in vivo at relevant anatomical sites and consequently whether FABP inhibition produces endocannabinoid- and NAE-mediated analgesia. Finally, in the last aim, we will examine changes in peripheral cytokine and prostaglandin levels that accompany FABP inhibition and determine whether FABP inhibition alters the sensitization of nociceptive neurons. In summary, this study will identify FABPs as novel proteins that regulate nociception and inflammation and will evaluate the roles for individual FABPs in endocannabinoid and NAE inactivation in vivo. By ascribing novel roles to FABPs in nociception, this work will provide a foundation for the development of future FABP targeting therapeutics that may lead to improved analgesics.